select max(编号) from t_Device
目的是要查询出编号最大的并赋值给temp变量,
并用Response.Write("<script>alert('temp')</script>");弹出一个对话框显示出当前temp值呢?求助
请各位看我写的怎么不对呢:con.Open();
SqlDataAdapter myAdapter = new SqlDataAdapter("select max(编号) from t_Device", con);
DataSet myDS = new DataSet();
myAdapter.Fill(myDS);
string ICAnum = myDS.Tables[0].Rows[0].ToString();有不对的地方么?
目的是要查询出编号最大的并赋值给temp变量,
并用Response.Write("<script>alert('temp')</script>");弹出一个对话框显示出当前temp值呢?求助
请各位看我写的怎么不对呢:con.Open();
SqlDataAdapter myAdapter = new SqlDataAdapter("select max(编号) from t_Device", con);
DataSet myDS = new DataSet();
myAdapter.Fill(myDS);
string ICAnum = myDS.Tables[0].Rows[0].ToString();有不对的地方么?
/// 获取某表的某个字段的最大值
/// </summary>
/// <param name="FieldName">字段名</param>
/// <param name="TableName">表明</param>
/// <returns>返回最大值</returns>
public static int GetMaxID(string FieldName, string TableName)
{
string strsql = "select max(" + FieldName + ")+1 from " + TableName;
object obj = SqlHelper.GetSingle(strsql);
if (obj == null)
{
return 1;
}
else
{
return int.Parse(obj.ToString());
}
}
/// <summary>
/// 执行一条计算查询结果语句,返回查询结果(object)。
/// </summary>
/// <param name="SQLString">计算查询结果语句</param>
/// <returns>查询结果(object)</returns>
public static object GetSingle(string SQLString)
{
using (SqlCommand cmd = new SqlCommand(SQLString, GetConn()))
{
try
{
object obj = cmd.ExecuteScalar();
if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
{
return null;
}
else
{
return obj;
}
}
catch (System.Data.SqlClient.SqlException e)
{
throw e;
}
} }
直接传t_Device和编号进去就行了。。
int ICAnum =GetMaxID(编号,"t_Device");